PDO Query using Propel

pdoQuery.php

 $sql = "[INSERT QUERY HERE]";

      $stmt = Propel::getConnection()->prepare($sql);
      $stmt->execute();
      $res = $stmt->fetchAll(PDO::FETCH_BOTH);

      foreach($res as $row)
      {
        // ... $pippo = $row['column_name'] 
        // o
        // ... $pippo = $row[2] 
      }